For 27 years it has targeted African-American kids from low-income families, children who otherwise could not afford the tuition at a private or religious school.

The vouchers are issued by what's known as the Milwaukee Parental Choice Program. Some people see them as a beacon of hope in a public school district where student achievement lags far behind the state average and where only 20 percent of students are proficient in English language arts and fewer than 15 percent in math.

Others say the program is a failed experiment that has siphoned away money desperately needed by the city's struggling schools.

As part of our reporting on vouchers around the country, and to get a look at the program as it stands today, we visited several schools in the voucher program.

Texas Bufkin Christian Academy has operated for 16 years. It occupies an old building that once housed a nursing home. The school's founder, Texas Bufkin, is wary of visitors, especially reporters.

"We don't let people from the media in our building," says Bufkin. Why? I ask. "Because I just don't feel like I need to talk to reporters." Eventually, I'm allowed inside but, Bufkin says, just for a few minutes.

Of the 121 private and religious schools in Milwaukee's voucher program, this is the lowest-performing, according to state education officials.

All of the 94 students enrolled from pre-K to 12th grade are African-American, Bufkin says.

All have a voucher worth up to $7,900, depending on the grade they're in. The school's latest scores on state tests show that not a single student is at grade level: not in math, not in reading, science or social studies, according to state education officials.

Bufkin's daughter, Nicole, who helps run the school, says there's a reason for the students' poor performance: Most of the children that the school takes in arrive four to six years behind.

"The child who's not a great student, the child that's just falling through the cracks — they may not be going to Harvard, they may not be going to Yale," she says. "But we're the people who are the net, and we're catching them."

Howard Fuller, who helped write the voucher law back in 1990, agrees that some voucher schools are doing no better than the city's public schools.

He should know. Fuller is a former superintendent of Milwaukee's school district. But he insists that for most of the 28,000 students in the program, vouchers are a lifeline.

"There are thousands of children whose lives are much better today because they were able to access better schools than they would have had if the voucher program had not existed," says Fuller.

His support for vouchers is pretty straightforward.

"I don't believe that we should have an America where only those of us with money have the ability to choose."

While vouchers in Milwaukee have definitely given poor families more choices, have they given children a better education?

Critics and supporters can both find, in the thick stacks of research on the program over the years, support for their arguments. That debate has long been muddied by ideologicial, and methodological, differences.

Over the years much of the research found test scores flat, lower in some cases or slightly improved in others. Some more recent studies have shown students in the program making modest gains compared with children in the city's public schools, especially in terms of college attendance and high school graduation.

But it has not over the years produced the large benefits in achievement that some had predicted. There's been no miracle here, says Wendell Harris, a member of the Milwaukee school board. He says one group that has benefited from vouchers is private and religious schools.

"If you set up a Christian academy and your main interest is to get a few hundred children to improve your [school finances]," he argues, "and you use Christianity as the draw, these schools have exploited persons' beliefs for their own private gain."

The rates of joblessness, crime and poverty in Milwaukee are among the highest in the nation. Vouchers don't address any of that, says Harris.

Fuller and other voucher proponents agree that the program needs to weed out the lowest-performing schools and build support for the best ones.

Schools like St. Marcus Lutheran School, just north of downtown Milwaukee. Almost all the students at St. Marcus are African-American. Nine out of 10 are low income, so they qualify for a voucher that helps cover the $8,500 tuition.

The school doesn't offer transportation, so Henry Tyson, the man who runs St. Marcus, is known to shuttle kids to and from school whenever their parents can't. This morning, he is on his way to pick up a little boy named Jeremiah. Tyson says Jeremiah is a talented child who lives in a rough neighborhood where kids often get lost.

"It's one of the great tragedies in a city like this," says Tyson. "How do you give kids a vision for their future especially when they're growing up in these tough, tough neighborhoods."

Margaret Katherine has a grandson at St. Marcus. The voucher that he uses was an opportunity she says she couldn't pass up.

"You better grab it while you can," she says, "because once it's gone, you're gonna be like me."

Katherine says not a day goes by that she doesn't regret dropping out of school, not learning how to read or write properly. "I don't want my child to be lost."

For her, all this back and forth about vouchers is not about pitting private schools against Milwaukee Public Schools.

"I don't want to see MPS fail, but I don't want my child to fail either," she says.

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AUDIE CORNISH, HOST:

Giving a family a school voucher doesn't guarantee a child a better education. We're about to hear how Milwaukee's African-American community has been struggling with this. The city has the nation's longest-running publicly funded voucher program. And for 27 years, it's targeting children who otherwise could not afford the tuition at a private or religious school. NPR's Ed team has been looking into vouchers, and Claudio Sanchez has our next report.

CLAUDIO SANCHEZ, BYLINE: Milwaukee's $202 million parental choice program is either a beacon of hope for poor children or a failed experiment. To figure out which is closer to the truth, we set out to visit a few voucher schools, starting in Texas Bufkin Christian Academy and its founder Texas Bufkin.

TEXAS BUFKIN: We don't let people from the media in our building.

SANCHEZ: Why?

BUFKIN: Because I just don't feel like I need to talk to reporters.

SANCHEZ: For good reason. Of the 121 private and religious schools in the voucher program here, this is the lowest performing. OK, five minutes, Bufkin says finally; I'll give you five minutes.

Texas Bufkin Christian Academy has operated for 16 years. It occupies an old drab building that once housed a nursing home for the blind. The narrow hallways are lined with half empty boxes. The lighting is poor. The school enrolls only 94 students, pre-K through 12th grade. It's one of two for-profit schools in the voucher program.

BUFKIN: You know, God has things for us to do - each and every one of us. And I think for me it is to be an educator. It is to bring some hope.

SANCHEZ: All the students here are African-American. All have a voucher worth up to $7,900. But the school's latest scores on state tests show that not a single student - zero - is at grade level - not in math, not in reading, science or social studies. The reason - Texas Bufkin's daughter, Nicole, who helps run the schools, says most of the students they take in arrive four to six years behind.

NICOLE BUFKIN: The child who's, like, not a great student, who's not in criminal trouble, but a child who's just fallen through the cracks, they may not be going to Harvard. They may not be going to Yale. But we're the people who are the net, and we're catching them.

SANCHEZ: Still, it's a bit of a mystery why the school has been allowed to remain in the voucher program given its dismal academic record. Turns out, the state can and has shut down voucher schools for health, safety and financial reasons but not because they were failing academically. It's how the voucher law was written.

Howard Fuller, one of the architects of the law, agrees. Some voucher schools are doing no better than the worse public schools. Fuller should know. He's a former superintendent of the Milwaukee public schools. But he insists that for nearly 28,000 kids - a third of the city's total student population - vouchers are a lifeline.

HOWARD FULLER: There are thousands of children whose lives are much better today because they were able to access better schools than they would have if the voucher program had not existed.

SANCHEZ: Fuller's support for vouchers is pretty straightforward.

FULLER: I don't believe that we should have an America where only those of us with money have the ability to choose.

SANCHEZ: But that's the thing. Vouchers here have simply not had the impact on students' overall academic performance that many predicted.

WENDELL HARRIS: My argument with Dr. Fuller was that if school choice became the law of the land in Wisconsin, the Catholic community would use the opening to, in essence, save the Catholic schools.

SANCHEZ: Many schools today rely so heavily on vouchers, they wouldn't exist without them, says Harris.

HARRIS: If you set up a Christian Academy, and your main interest is to get 100 children to improve your economic status using Christianity as the draw to exploit a person's beliefs for your own private gain, education is secondary.

SANCHEZ: Harris was one of the original plaintiffs who back in the 1990s sued the state in a failed effort to block vouchers. To this day, he and other black leaders in Milwaukee believe that the push for vouchers was not entirely about rescuing poor children.

HARRIS: Their agenda was to undermine public trust and public education in order to get to where they are now. Many of those families are convinced that public education is the problem. They don't understand that the problem is bigger than the school system.

SANCHEZ: Joblessness, crime and Milwaukee's poverty rates are among the highest in the nation. Vouchers don't address any of this, says Harris. As a prominent member of the NAACP, that's why he says he supports the group's call for a moratorium on charters and vouchers.

FULLER: That's absurd. What the hell are we talking about it here, man? The NAACP don't represent all black people.

SANCHEZ: Again, Howard Fuller.

FULLER: There's thousands and thousands and thousands and thousands and thousands of black parents who are going to exercise the best option for their children, and they don't care what the NAACP says.

SANCHEZ: Voucher proponents say they want to weed out the lowest performing voucher schools and build support for the best ones like St. Marcus, a Lutheran school just north of downtown.

HENRY TYSON: So right now we're just leaving the school...

SANCHEZ: Henry Tyson runs St. Marcus. This morning he's on his way to pick up a little boy who can't get to school because his mom's car broke down. The boy's name is Jeremiah.

TYSON: A boarded up house on the right, a lot of trash in the streets. This is a tough, tough neighborhood right here that Jeremiah lives in.

SANCHEZ: Tyson says there are many Jeremiahs at St. Marcus, where 9 out of 10 students receive a voucher to help cover the $8,500 tuition.

TYSON: He loves school, just stacked with talent. And this, of course, is one of the great tragedies in a city like this. How do you give kids a vision for their future?

SANCHEZ: Claudio Sanchez, NPR News.

ARI SHAPIRO, HOST:

Next week the White House is expected to release an education budget request that increases spending for voucher programs. Education secretary Betsy DeVos is a big supporter of these programs.

(SOUNDBITE OF ARCHIVED RECORDING)

BETSY DEVOS: I'm a firm believer that parents should be empowered to choose the learning environment that's best for each of their individual children.

CORNISH: She spoke of school choice and vouchers during her confirmation hearing earlier this year.

(SOUNDBITE OF ARCHIVED RECORDING)

DEVOS: If a school is troubled or unsafe or not a good fit for a child, perhaps they have a special need that's going unmet. We should support a parent's right to enroll their child in a high-quality alternative.

CORNISH: But do voucher programs really provide high-quality alternatives? NPR's Ed team found that it's hard to prove whether vouchers will brighten a child's academic prospects.

SHAPIRO: Part of the problem is that it's hard to separate the performance of a school from the selection of its students. Many private schools have an application process for students and stricter discipline codes. And private schools tend to enroll fewer students with disabilities.

CORNISH: Another big challenge - many of the studies rely solely on test scores, which provide an incomplete picture of why families might choose a school, such as safety or a smaller class size.

SHAPIRO: So while it can be hard to determine whether school choice and voucher programs are working, most studies have not found much evidence that students benefit academically from these programs. In some cases, there may be a slight benefit - in other cases, just the opposite.